As this type of device, an FM demodulation situation display device is disclosed in Patent Document 1.
The FM demodulation situation display device disclosed in Patent Document 1 includes a display device that displays the frequency of an input FM signal when FM signal tuning adjustment is performed. The display device has a structure in which nine display units including one green display unit that emits green light and eight red display units that emit red light are arranged in a line in the horizontal direction. The green light emission unit is interposed between four right red light emission units and four left red light emission units and is disposed at the center of the display device.
The green light emission unit emits light when the center frequency of an input signal is within the target range (fc±Δfc) of a predetermined center frequency fc. When the center frequency of the input signal is less than (fc−Δfc), the four left red light emission units emit light according to the frequency. When the center frequency of the input signal is greater than (fc+Δfc), the four right red light emission units emit light according to the frequency.
According to this structure, the FM demodulation situation display device disclosed in Patent Document 1 can display the FM signal tuning adjustment such that the user can easily recognize it.